fighting lily leaf beetles organically

IDON’T USE CHEMICALS, but that doesn’t mean I don’t fight unwanted garden pests. At the moment the primary skirmish is with the lily leaf beetle, Licioceris lilii, who happens to be my favorite color–a sort of Asian lacquer red–but otherwise much-loathed here. And so these days, I am out hunting, on a search-and-destroy mission for the small but voracious pests who also like Fritillaria and Polygonatum (Solomon’s seal) and a number of other garden plants not captured in their common name. Ready for a fight? Onward, organic gardeners, onward…and don’t forget to get the beetle eggs, too. Here’s how:

Much in the same way I deal with everything from tomato hornworms to adult Japanese beetles to Viburnum leaf beetle and tent caterpillars and even the occasional slug in a wet year, my approach to lily beetles is manual–as in pick and squish, or drown.

You have to get the adults, and also the eggs, which start out tan and then go from orange to red when they are close to hatching. They can be found wherever there are copulating adults (which is anywhere that adult beetles are, it seems from their flagrant behavior), on the undersides of leaves in uneven lines like a bit of a tiny zig-zag. Squish!

Since the beetles overwinter in the soil, the minute lily or fritillaria foliage emerges, there are hungry beetles to damage it, too–meaning if they’re in your area, you probably are already seeing holes. Even if you didn’t get started right away, begin hand-picking beetles and eggs now to minimize the exploding population; remember, these are sexy beasts, so keep removing adults and eggs or else.

You see, I’ve left the worst for last: the part about what comes between the egg and the beetle. The larval stage of this pest is extremely ill-mannered, covering itself in its own excrement as if to just dare you to touch it. It is also the most voracious and therefore most damaging stage, so knock off those beetles and eggs now, and avoid the filthy little slug-like slobs altogether. Work fast when you pick, since adults will quickly disappear by flying off the plant and turning upside down in the soil as camouflage.

The use of parasitoid wasps to cripple the beetles has been very successful in European tests, and in a few research studies domestically, but is not available as a consumer product nor widespread enough yet to help in most areas. (The Rhode Island link below gives an update on states that have released various species of the parasitoids.) If you have more than a few clumps of lilies, lily leaf beetle can be controlled in some stages (particularly the youngest larvae) with spray products containing Neem. Me? I’ll just be out picking.

more details on lily leaf beetle

THE LILY LEAF BEETLE, of Asian origin, has founds its way into six Canadian provinces and as many states in the Northeast, most recently making its way into northern New York State (where I am).

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Hi. I love your posts. Non-related question: The front of my house has to get spray washed, and my property has been all organic for 10 years. Do you know what product I can use that is organic? The house has mossy, mold that has to come off.

They’ve been a terrible pest here in the real upstate NY/Finger Lakes region for years now. I’ve discovered by observation that they seem to overwinter in debris and litter, so I clean up as thoroughly as possible in fall, then make sure to put down fresh mulch around the lilies early in the spring. I also noticed that this year for the first time they seem to have declined somewhat – my fritillarias were largely unmolested, as were most of my lilies. Maybe, like the viburnum leaf beetle, they’re reaching a cyclical decline in the life cycle? We can only hope!

I live in Dutchess county NY and have had these bugs for two years now,but this year there was hardly any damage.The reason grasp and squish.I will try the cinnamon this spring,but I will stand guard.This is war.

I live in Webster, NY, and this is the first time I’ve seen them, and they’re all over my lilies. I’m used to bugs, so I just ignored them, until today when I noticed my lilies aren’t looking so great. What a drag!!!!!

My first sighting of lily beetles was last year after growing lilies for years. tried several insecticides & FOUND
SOAP SPRAY INSECTICIDE was best. If the beetles fall off the plant when sprayed is a good indication it is working. I now, also have a bag of Diatomaceous Earth to dust in between sprays & spread a dusting on ground around the plant should do the trick… I was horrified when I first saw them after they had eaten all the leaves all the way up the stock. What drew my attention was the birds were landing on the plants & picking away at the stems & commented to the wife on that was the first time I had seen birds on the lilies eating aphids (I thought) & 2 /3 days latter went over to check. Now I know & so do you .. lol

I live in Hamlin N.Y. I have had Asiatic Lilies in my garden for 12 years and never had a problem until this year! The devastation and damage happened seemingly overnight!!! I was shocked! Found and researched the critters, of course it is the work of the Red Lily Leaf Beetle!! I have removed all I could find by hand… but I know there is more, to much damage for just the pair! Any tips would be appreciated for this novice!!!!

It’s a horror, I know, Zena. Besides hand picking and crushing any eggs you see on the leaf undersides before they hatch, Neem-based products are supposed to be good for killing the young larvae (not the adult beetles), sprayed every 5-7 days. More on that and other controls hopefully coming soon.

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Welcome! I’m Margaret Roach, a leading garden writer for 25 years—at ‘Martha Stewart Living,’ ‘Newsday,’ and in three books. I host a public-radio podcast; I also lecture, plus hold tours at my 2.3-acre Hudson Valley (NY) Zone 5B garden, and always say no to chemicals and yes to great plants.